An algal strain, Nitzschia palea NY025, was chosen as experimental materials for its high-lipid content. The feasibility of optical density method used for cell growth determination was investigated first. Then Nile red fluorescence was used for determining the relative neutral lipid contents because neutral lipid content was a key standard of choosing algae in biodiesel production. Furthermore, the effects of temperature, light intensity, nitrogen, phosphorus and silicon on the cell growth and neutral lipid contents of N. palea were investigated. The results showed that: (1) The maximum absorption of N. palea existed at 675nm, and the absorption showed a good linear relationship with cell density. Therefore, the growth of N. palea could be obtained by measuring OD₆₇₅. Optical density method and Nile red fluorescence possessed advantage of simple operation, so they were suitable for high-throughput sample analysis. (2) The optimum temperature was 20℃ for increasing the cell density and neutral lipid content of N. palea. The finest light intensity for the growth of N. palea was 160 μmol m^-2s^-1, while the best light intensity for neutral lipid accumulation was 200 μmol m^-2s^-1. It is suggested that increasing light intensity appropriately might increase neutral lipid contents in algal cells. (3) Under the optimum temperature and light intensity, the orthogonal experiments of nitrogen, phosphorus and silicon were designed to research into their effects on the growth and neutral lipid contents of N. palea. The influence of nitrogen on the growth of N. palea was the most significant, then the factor phosphorus and the last one was factor silicon. The growth of N. palea was influenced significantly by factors nitrogen, phosphorus, silicon and interaction factors nitrogen with phosphorus, nitrogen with silicon. The optimum growth rate was obtained when the content of nitrogen, phosphorus and silicon were 80 mg/L, 120 mg/L and 100 mg/L, respectively. The influence of factor nitrogen on neutral lipid accumulation was the most significant, next was factor silicon and the last one was factor phosphorus. Neutral lipids accumulation was influenced significantly by factors nitrogen, silicon and interaction factors nitrogen with phosphorus, nitrogen with silicon. The maximum neutral lipid accumulation was obtained when the concentration of nitrogen, phosphorus and silicon were 80 mg/L, 120 mg/L and 50 mg/L, respectively. (4) In conclusion, the lipid synthesis can be improved by two-step method. First the cell density of N. Palea was increased, and after gathering plenty of cells the culture conditions changed to increase neutral lipid contents.